/*
 * Copyright (c) 2005, 2006, 2007 Lev Walkin <vlm@lionet.info>.
 * All rights reserved.
 * Redistribution and modifications are permitted subject to BSD license.
 */
#ifndef _PER_SUPPORT_H_
#define _PER_SUPPORT_H_

#include <asn_system.h> /* Platform-specific types */

#ifdef __cplusplus
extern "C"
{
#endif

    /*
 * Pre-computed PER constraints.
 */
    typedef const struct asn_per_constraint_s
    {
        enum asn_per_constraint_flags
        {
            APC_UNCONSTRAINED = 0x0,    /* No PER visible constraints */
            APC_SEMI_CONSTRAINED = 0x1, /* Constrained at "lb" */
            APC_CONSTRAINED = 0x2,      /* Fully constrained */
            APC_EXTENSIBLE = 0x4        /* May have extension */
        } flags;
        int range_bits;     /* Full number of bits in the range */
        int effective_bits; /* Effective bits */
        long lower_bound;   /* "lb" value */
        long upper_bound;   /* "ub" value */
    } asn_per_constraint_t;
    typedef const struct asn_per_constraints_s
    {
        struct asn_per_constraint_s value;
        struct asn_per_constraint_s size;
        int (*value2code)(unsigned int value);
        int (*code2value)(unsigned int code);
    } asn_per_constraints_t;

    /*
 * This structure describes a position inside an incoming PER bit stream.
 */
    typedef struct asn_per_data_s
    {
        const uint8_t *buffer; /* Pointer to the octet stream */
        size_t nboff;          /* Bit offset to the meaningful bit */
        size_t nbits;          /* Number of bits in the stream */
        size_t moved;          /* Number of bits moved through this bit stream */
        int (*refill)(struct asn_per_data_s *);
        void *refill_key;
    } asn_per_data_t;

    /*
 * Extract a small number of bits (<= 31) from the specified PER data pointer.
 * This function returns -1 if the specified number of bits could not be
 * extracted due to EOD or other conditions.
 */
    int32_t per_get_few_bits(asn_per_data_t *per_data, int get_nbits);

    /* Undo the immediately preceding "get_few_bits" operation */
    void per_get_undo(asn_per_data_t *per_data, int get_nbits);

    /*
 * Extract a large number of bits from the specified PER data pointer.
 * This function returns -1 if the specified number of bits could not be
 * extracted due to EOD or other conditions.
 */
    int per_get_many_bits(asn_per_data_t *pd, uint8_t *dst, int right_align,
        int get_nbits);

    /*
 * Get the length "n" from the Unaligned PER stream.
 */
    ssize_t uper_get_length(asn_per_data_t *pd,
        int effective_bound_bits,
        int *repeat);

    /*
 * Get the normally small length "n".
 */
    ssize_t uper_get_nslength(asn_per_data_t *pd);

    /*
 * Get the normally small non-negative whole number.
 */
    ssize_t uper_get_nsnnwn(asn_per_data_t *pd);

    /* X.691-2008/11, #11.5.6 */
    int uper_get_constrained_whole_number(asn_per_data_t *pd, unsigned long *v, int nbits);

    /* Non-thread-safe debugging function, don't use it */
    char *per_data_string(asn_per_data_t *pd);

    /*
 * This structure supports forming PER output.
 */
    typedef struct asn_per_outp_s
    {
        uint8_t *buffer;      /* Pointer into the (tmpspace) */
        size_t nboff;         /* Bit offset to the meaningful bit */
        size_t nbits;         /* Number of bits left in (tmpspace) */
        uint8_t tmpspace[32]; /* Preliminary storage to hold data */
        int (*outper)(const void *data, size_t size, void *op_key);
        void *op_key;         /* Key for (outper) data callback */
        size_t flushed_bytes; /* Bytes already flushed through (outper) */
    } asn_per_outp_t;

    /* Output a small number of bits (<= 31) */
    int per_put_few_bits(asn_per_outp_t *per_data, uint32_t bits, int obits);

    /* Output a large number of bits */
    int per_put_many_bits(asn_per_outp_t *po, const uint8_t *src, int put_nbits);

    /*
 * Flush whole bytes (0 or more) through (outper) member.
 * The least significant bits which are not used are guaranteed to be set to 0.
 * Returns -1 if callback returns -1. Otherwise, 0.
 */
    int per_put_aligned_flush(asn_per_outp_t *po);

    /* X.691-2008/11, #11.5 */
    int uper_put_constrained_whole_number_s(asn_per_outp_t *po, long v, int nbits);
    int uper_put_constrained_whole_number_u(asn_per_outp_t *po, unsigned long v, int nbits);

    /*
 * Put the length "n" to the Unaligned PER stream.
 * This function returns the number of units which may be flushed
 * in the next units saving iteration.
 */
    ssize_t uper_put_length(asn_per_outp_t *po, size_t whole_length);

    /*
 * Put the normally small length "n" to the Unaligned PER stream.
 * Returns 0 or -1.
 */
    int uper_put_nslength(asn_per_outp_t *po, size_t length);

    /*
 * Put the normally small non-negative whole number.
 */
    int uper_put_nsnnwn(asn_per_outp_t *po, int n);

#ifdef __cplusplus
}
#endif

#endif /* _PER_SUPPORT_H_ */
